These spy pens will please any young secret agent with their high tech functions. The Hidden Ink Pen allows you to mark cash, write secret messages, codes, phone numbers, etc. without worrying about the information being seen. The ink is invisible until examined under the UV "spy light". Spy Listening Pen can be used for recording messages, complete with special sound effects incorporated into the pen memory. Spy Eavesdropping Pen allows you to hear and enhance voices from a distance. Comes with volume control and earphones. All button batteries are included. Set of three individually packaged spy pens.